Heat-treating container



May 11, 1954 B. SHEETZ HEAT-TREATING CONTAINER Filed May 18, 1953 INVENTOR. Lloyd B.Sheetz.

ATTORNEY Patented May 11, 1954 HEAT-TREATIN G CONTAINER ,Lloyd B. Sheetz, Conway, Pa., assignor to Allegheny Lndlum Steel Corporation, Brackenridge, Pa., a. corporation of Pennsylvania Application May 18, 1953, Serial No. 355,504

Claims. (01. 266-6) This invention relates to improvements in containers and in particular to metallic containers for conveying a billet through a heat-treating salt bath.

Heretofore, attempts have been made to utilize highly alloyed steels in forming containers for conveying steel billets through a heat-treating salt bath. These containers have been fabricated from bars and rods, usually welded, into container form. However, stress concentrations at sections of reduced cross-sectional area and sharp corners and at the welded joints, combined with the corrosive attack of the salt bath have resulted in failures of the containers after very short periods of service. The time to failure is accelerated by the high operating temperatures encountered in heat treating the billets in the salt bath. Further, while the container must be sufficiently strong to support the weight of the billet to be treated, it must also provide ready access to the billet for the salt bath to effectively heat treat the billet, and at the same time, provide adequate drainage of the molten salt bath when the container holding the billet is removed from the bath.

An object of this invention is to provide a metallic container for conveying a billet through a heat-treating salt bath.

Another object of this invention is to provide a container for conveying a billet through a heat-treating salt bath, the container having open ends to permit access of the salt bath to the billet.

A further object is to. provide a container for conveying a billet through a heat-treating salt bath, the container having a minimum of welded joints and sections of reduced cross-sectional area and sharp corners which contribute to stress concentrations.

A more specific object of this invention is to provide a container for conveying a billet through a salt bath, the container being composed of carbon steel having a minimum of welded joints and stress concentration areas and having open ends for providing access for the salt bath to thebillet and a non-rigid support for facilitating loading and unloading; of the container.

Other objects will become apparent to those- Fig. 3 is a view in development illustrating an expanded shape of the container.

Referring to the drawing and in particular to Fig. 1 thereof, this invention is illustrated by reference to the container shown generally at [0 for conveying a billet I2 of metal contained therein through a salt bath (not shown) for heat treating the billet I2. The container l0 comprises a substantially cylindrical side wall member l4 having open upper and lower ends 15 and 18, respectively. The cylindrical side wall member I4 is preferably formed from a carbon steel pipe, the carbon steel being of the SAE 1000 series, wherein the upper end I6 of the cylindrical side wall member [4 is shaped in a substantially sinuous manner to provide a pair of opposing upwardly extending appendages 20 and 22. The spaces or notches 24 and 26 between the opposing appendages 20 and 22 are formed in a substantially reverse curved manner as illustrated more clearly in Fig. The reverse curved notch portions 24 and 26 extend downward a sufficient distance along the side wall member so that the ends of each of the notches 24 and 26 are below the upper end portion of the billet l2. It will be appreciated that any notched configuration of general sinuous shape may be employed in forming the upper end [6 of the container 10. However, it is essential that there be no sharp corners or sections of reduced cross-sectional area which contribute to stress concentrations and accelerate the time to failure. At the same time, there must be sufficient physical structure to support the weight of the billet l2 while providing adequate access of the salt bath (not shown) to the billet I2, for obtaining a proper heat treatment of the billet 12. The

upwardly extending appendages 20 and 22 are provided with diametrically opposed openings 28 and 30, respectively, of curved configuration therethrough whose function will hereinafter be more fully described. The openings 28 and may be formed in any manner, however, drilling is preferred since it eliminates sharp corners.

The lower end I8 of the cylindrical side wall member I 4 is also shaped in a substantially sinuous manner to provide downwardly extending op posing appendages 32 and 34 having reverse curved notch portions 36 and 38 therebetween. The notched portions 36 and 38 are aligned with the notched portions 24 and 26, respectively, of the upper end portion [6. The notched portions 36 and 38 are disposed as illustrated to. extend upwardly to expose the bottom edge of. the billet [2 when positioned in the container It]. In forming the aligned notched portions 24-36 and) 26-48, there must be sufiicient side wall material between the extremities of the aligned notched portions 24-36 and 26-38 so that stress concentrations which may exist by virtue t reduced cross-sectional area are minimized without interfering with or preventing access of the salt bath (not shown) to the billet [2 in the container H]. Further, the lower extremities 40 and d2 of the downwardly extending appendages 32 and 34, respectively, are formed perpendicular to the longitudinal axis of the container I!) to provide feet for the container l0 whereby it may rest in an upright position when removed from 4 detected upon periodic inspection. As long as either the weld or the bolt assemblies remains intact, either will have sufiicient strength to carry the billet l2 within the container I 0 through and out of the salt bath (not shown).

The container I6 is also provided with a pair of non-rigid suspension means 12 and 14 of carbon steel disposed to have one end connected to the rigid straps 56 and 58, respectively, by any suitable means, for example, by bolt and nut fastening assemblies H and I3 disposed through the openings 62 and 66, respectively, the other end being pivotally connected by any suitable means to a carrying bar means 15. Since the non-rigid suspension means 12 and M are not immersed in the salt bath (not shown) nor are they subject to high operating temperatures, the

will hereinafter be'more fully described. The" plurality of slots 4448 and 46--59 are formed by drilling the appendages 32 and 34, respectively, to form the upper and lower spaced portions of the slots and thereafter cutting the intermediate material between the spaced drilled portions to provide a slot having a lateral opening having a width equal to the diameter of the drilled portions of the slots. This will provide a somewhat elliptical-shaped slot characterized by the absence of sharp corners. All of the slots 44, 45, B8 and 50 are formed in a similar manner.

In order to support the billet H2 in an upright position Within the container N, a plurality of bar mean 52 and 54 are disposed in spaced relation to extend across the bottom portion it with the ends of the bars projecting through the slots iii-5t and 4-46, respectively, in the downwardly extending appendages 32 and 34. The bar means 52 and 54 are composed of carbon steel of the SAE 1000- series and are of sufficient crosssectional area to support the billet l2 when the container IE] is immersed in the salt bath (not shown) operating at high temperatures. The ends of the bar means which extend beyond the downwardly extending appendages 32 and 34 are secured in position to the side wall member id as by peening. When desired, the ends of the bar means 52 and 54 may also be Welded to the associated downwardly extending appendages.

In order to suspend the container IQ within the salt bath (not shown), a pair of rigid straps 55 and 58 are secured to the upwardly extending appendages 2i! and 22, respectively. The rigid straps 56 and 58 are preferably composed of stainless steel and are provided with openings 89-82 and 64-E6, respectively, near the ends thereof. The openings fill and 64 in the rigid straps 56 and 58, respectively, are aligned with the openings 28 and 38, respectively, in the up' wardly extending appendages 2i) and 22, respectively, to facilitate securing the straps thereto as by means of the bolt and nut assemblies 61 and 59. Since in practice the container IE] will be immersed in the salt bath (not shown) to a predetermined height on the rigid straps 5B and '53 and since the rigid straps 56 and 58 have the smallest cross-sectional area of the portion of the container it which is to be immersed and are subject to the highest stress concentration, they are adapted for easy replacement. Where desired, the rigid straps 56 and 58 may be welded to the upwardly extending appendages and 22 in addition to being bolted. The double connection of the bolting and welding is desired since it is unlikely that both connections will fail simultaneously and the failure of either can be readily problem of stress concentration is of no concern. Instead of forming the suspension means 72 and 74 of carbon steel, since they will be exposed to a corrosive atmosphere when the container I0 is immersed in the salt bath (not shown), the suspension means l2 and M may be composed of stainless steel in the form of a cable or a link belt. The bar means it is adapted for easy connection to any of the well-known conveyance mechanisms (not shown) for movement through the salt bath (not shown).

In forming the container A B, a template of the proper dimensions is made that is quite similar to the development view illustrated in Fig. 3. The template is placed in position around a carbon steel pipe and the pipe is out according to the dictates of the template. The slots 4448 and Git-5i) as well as the holes 28 and 30 are then formed as hereinbefore set forth. The bar means 52 and 54 are then disposed across the bottom of .the container ii] to extend through the slots i -5B and 44- 36, respectively, and the ends of such bars are peened or welded to the side wall member 14. The rigid straps 56 and 5B are then secured to the upwardly extending appendages 28 and 22, respectively, by means ofthe bolt and nut assemblies 61 and 65!. The non-rigid support means '12 and M are then removably secured to the rigid straps 56 and 58, respectively, by the bolt and nut assemblies 1! and 13 passed through the openings E2 and 66. The other ends of the non-rigid support means '52 and Marc connected to the bar means 16 disposed therebetween.

The container Iii standing on end is then disposed to receive the billet 12 therein. The nonrigid support means 12 and 14 are secured by the bar means it to any of the well-known conveyer mechanism (not shown) and the container is is moved into, through, and out of the heattreating salt bath (not'shown) in response to the movement of suchconveyer mechanism.

The container of this invention has the economic advantage of being formed from a carbon steel pipe as opposed to theprior art containers of high alloyed steel and/0r complicated struc ture. Further, since the container of this invention does not possess any sharp corners nor sections of reduced cross-sectional area which are points of stress concentration except possibly the readily replaceable rigid supporting straps, it is found that the container has a life greatly in excess of any of the known containers at only a fraction of thecostof such known containers. My container is also efiicientinoperation, the

notches in the upper and lower ends thereof providing ready access of thesalt bath to the billet for proper heat treatmentwhile the container confines the billet in an upright manner during movement through the salt bath.

I claim:

1. In a container, the combination comprising, a substantially cylindrical side wall member having open ends, the side wall member having each of its ends notched in a predetermined manner to provide access through the side wall at the ends thereof to the space formed by the side wall member, bar means disposed across one of the open ends to form a support, the notches of said one end overlapping the bar means to provide access to said space within the side wall member, and means connected to the other end of the side wall member between the notches therein for carrying the side wall member.

2. In apparatus for use in conjunction with a movable support for conveying a billet through a heat-treating medium, the combination comprising, a container disposed to receive a billet, the container having a cylindrical side wall member formed with open ends, bar means disposed across one of the ends to support the billet within the side wall member, each of the ends of the side wall member being notched to provide access for the heat-treating medium therethrough to the billet when the container is immersed in the heattreating medium, and non-rigid means secured to the other notched end of the side wall member disposed to be secured to the movable support whereby the container is moved through the heattreating medium in response to the movement of the movable support.

3. In apparatus for use in conjunction with a movable support for conveying a billet through a heat-treating salt bath, the combination comprising, a container disposed to receive the billet, the container having a cylindrical side wall member formed with open ends, both of the ends of the container side wall being formed in a general sinuous manner, said side wall member being formed from a carbon steel pipe, bar means disposed across one of the open ends to support the billet within the side wall member, said bar means being composed of carbon steel, each of the ends of the container being open to permit access of the heat-treating salt bath therethrough to the billet when the container is immersed in the heattreating medium, a pair of rigid straps secured to the other end of the container, said rigid straps being composed of stainless steel, and a non-rigid suspension means disposed to connect the rigid straps to the movable support whereby the container is moved through the heat-treating salt bath in response to the movement of the movable support, said container being characterized by the economic use of common inexpensive materials and long life when used, in the salt bath.

4. In a container, the combination comprising, a substantially cylindrical side wall member having open ends of a general sinuous form disposed to provide opposing appendages, the side wall member being formed from a carbon steel pipe, the opposing appendages of the ends being disposed to permit access through the side wall member at the ends thereof to the space formed by the side wall member, a pair of bar members disposed in spaced relation to extend through the appendages at one end of the side wall member, said bar members being composed of carbon steel, and means connected to the appendages of the other end of the side wall member for carrying the side wall member, said carrying means being composed of stainless steel.

5. In apparatus for use in conjunction with a movable support for conveying a billet through a heat-treating salt bath, the combination comprising, a substantially cylindrical side Wall member having open ends, the side Wall member having each of its ends formed in a sinuous manner to provide access through the side wall at the ends thereof to the space formed by the side wall member, bar means disposed across one of the'open ends to form a support, the notches of said one end overlapping the bar means to provide access to said space within the side wall member, and means connected to the other end of the side wall for carrying the side wall member, said means for carrying the side wall member being composed of stainless steel and secured to the side wall member by welding and bolting for easy and economical replacement.

N 0 references cited. 

